In a trend that might have long-term implications for the U.S. multifamily industry, and the senior housing subset, Pew Research has found that American adults are increasingly sharing a home with other adults with whom they are not romantically involved. The initial uptick in shared living arrangements is associated with the wake of the Great Recession, but nearly a decade later, shared living has continued to grow.

Once upon a time, during the worst employment market in recent memory in the early 2010s, shared living grew because Millennials moved back in with their parents, and so it was considered a temporary flux in living arrangements. Now parents are moving in with their adult children in no small numbers, and it might be the beginning of a more permanent trend.

In 2017, the report noted, nearly 79 million adults (31.9 percent of the adult population) lived in a shared household, which is one with at least one adult who is not the household head, the spouse or unmarried partner of the head, or student between 18 and 24. In 1995, 55 million adults (28.8 percent) lived in a shared household.

“Adults who live in someone else’s household typically live with a relative,” the report said. “Today, 14 percent of adults living in someone else’s household are a parent of the household head, up from 7 percent in 1995.”

Also, and probably not coincidentally, U.S. household formation—or the number of households for every 100 adults—has recently fallen to anemic levels for several age groups. In 2017, for example, there were 31 households headed by an adult younger than 35 for every 100 adults in that age bracket, which is among the lowest rate of household formation for this age group since the early 1970s.